Method and system for classification of photo-plethysmographically detected respiratory effort

• US 9,044,558 B2
• Filed: 02/01/2013
• Issued: 06/02/2015
• Est. Priority Date: 03/24/2008
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Covidien LP (Medtronic Plc)
• Inventors: Baker, Clark R. Jr., O'Neil, Michael P., Campbell, Shannon E., Hausmann, Gilbert
• Primary Examiner(s): Anderson, Lynne
• Assistant Examiner(s): PHILIPS, BRADLEY H
• Application Number:
  US13/757,564
• Publication Number:
  US 20130146056A1
• Time in Patent Office: 851 Days
• Field of Search: 12820418-20423, 128/200.24
• US Class Current: 1/1
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/4818 Sleep apnoea
• CPC Class Codes: A61B 5/726 using Wavelet transforms
• CPC Class Codes: A61M 16/0003 Accessories therefor, e.g. sensors, vibrators, negative pressure
• CPC Class Codes: A61M 16/0057 Pumps therefor
• CPC Class Codes: A61M 16/0069 the speed thereof being controlled by respiratory parameters, e.g. by inhalation
• CPC Class Codes: A61M 2205/18 with alarm
• CPC Class Codes: A61M 2205/33 Controlling, regulating or measuring
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: A61M 2230/20 Blood composition characteristics
• CPC Class Codes: A61M 2230/205 partial oxygen pressure (P-O2)
• CPC Class Codes: A61M 2230/40 Respiratory characteristics

Abstract

Embodiments disclosed herein may include systems and methods for determining a patient'"'"'s respiratory effort and blood oxygen saturation based on data acquired from a pulse oximetry sensor and analyzing the parameters in conjunction with each other. For example, the respiratory effort may be determined based on a photo-plethysmographic waveform generated from light attenuation detected by the sensor, and the blood oxygen saturation may be a pulse-based estimate of arterial blood oxygen saturation determined from the detected attenuation. Analysis of the parameters may enable detection and classification of apnea (e.g., obstructive or central) or another underlying cause for respiratory instability. Furthermore, the measured respiratory effort may be compared to respiratory effort supplied by a ventilator to ensure proper sensor placement before enabling automatic adjustment of ventilator settings.

Claims

1. A processor-implemented method comprising:

operating a ventilator attached to a patient based at least in part on a ventilator setting to generate a desired respiratory effort;

analyzing a plethysmograph signal to determine information corresponding to an actual respiratory effort;

automatically adjusting the ventilator setting based on blood oxygen saturation of the patient;

determining whether a desired relationship exists between the information corresponding to the actual respiratory effort and the desired respiratory effort;

suspending ventilator adjustments when the desired relationship is determined not to exist; and

maintaining the ventilator setting when the desired relationship is determined not to exist.

2. The method of claim 1 wherein determining whether a desired relationship exists between the information corresponding to the actual respiratory effort and the desired respiratory effort comprises determining whether a relationship exists between the ventilation phase of the ventilator and the actual respiratory effort.

3. The method of claim 1 wherein determining whether a desired relationship exists between the information corresponding to the actual respiratory effort and the desired respiratory effort comprises determining whether a relationship exists between the ventilation rate of the ventilator and the actual respiratory effort.

4. The method of claim 1 further comprising:

generating a sensor placement alarm signal when the desired relationship is determined not to exist.

5. The method of claim 1 wherein the blood oxygen saturation is determined based at least in part on the plethysmograph signal.

6. A system comprising:

a ventilator attached to a patient configured to operate based at least in part on a ventilator setting to generate a desired respiratory effort; and

a monitor configured to;

analyze a plethysmograph signal to determine information corresponding to an actual respiratory effort,

automatically adjust the ventilator setting based on blood oxygen saturation of the patient,

determine whether a desired relationship exists between the information corresponding to the actual respiratory effort and the desired respiratory effort,

suspend ventilator adjustments when the desired relationship is determined not to exist,

and maintain the ventilator setting when the desired relationship is determined not to exist.

7. The system of claim 6 wherein the monitor is further configured to determine whether a relationship exists between the ventilation phase of the ventilator and the actual respiratory effort.

8. The system of claim 6 wherein the monitor is further configured to determine whether a relationship exists between the ventilation rate of the ventilator and the actual respiratory effort.